DE102004029167A1 - Seat adjustment device, and method for operating such - Google Patents

Abstract

Seat adjustment device (10) and method for operating such, with two relative to each other and / or with respect to a mounting surface (12, 14) movably arranged seat parts (15, 16, 17, 18, 19) via at least one ratchet mechanism (56) with each other wherein the ratchet mechanism (56) has a double-acting rotary drive (54), and the rotary drive (54) by means of a connecting element (52, 64, 72, 78) with at least one pneumatic linear actuator (52) is operatively connected when applied contracted axially with a pressure (42, 43) and thereby causes the rotary drive (54) to rotate.

Description

The The invention relates to a seat adjustment, in particular for motor vehicle seats, and a method of operating such a genus the independent one Claims.

With the DE 100 16 618 A1 is a double-acting drive for generating a rotational movement has become known, as used for manual seat adjustment in the motor vehicle. Starting from a zero point position of a pivotable drive lever, the drive can be rotated either in one or the other direction of rotation. The drive has an output member which is rotated only when the drive lever moves away from the zero point position, while the output member is not taken in a movement of the drive lever to the zero point position. In this case, a manually generated torque is transmitted to the output element according to the ratchet principle. The provision of the drive lever takes place via a spring element which is designed as a compression spring.

From the EP 1209366 B1 a pneumatic actuator is known which comprises an axially and radially elastic hose which increases its diameter by pressurization and thereby shortens its length. This change in length is used to open a hood of a motor vehicle. The disadvantage here is that the pneumatic actuator causes only a single adjustment to the length difference of the hose. Likewise, in such an embodiment, only one turn in one direction (opening the hood) can be made by means of the pneumatic actuator.

Advantages of invention

The seat adjustment device according to the invention, and the method of actuation such having the characterizing features of the independent claims the advantage that by the arrangement of the pneumatic linear actuators the connecting element of the rotary drive a ratchet mechanism automatically operated which can actuate a rotary drive in both directions. This allows a seat part or a vehicle seat in both directions, for example, forward and backward or up and down, pressed become. Since the linear actuator is coupled to the ratchet mechanism, can by repeatedly pressing of the linear actuator rotates around any angle, and with it be generated by any adjustment of the seat part. There in many motor vehicles as standard a pneumatic pressure supply already exists, deleted Here are a variety of electric motors in the automatic seat adjustment. Such pneumatic linear actuators are due to the flexible Hose variable to install in the seat and have a lower Weight as comparable electric motors. The inventive pneumatic Linear drive can be particularly favorable for existing ones Seat frames are used, which were previously adjusted manually. Another advantage of the pneumatic linear actuators is their low Noise, whereby the ride comfort of the motor vehicle is improved.

By in the subclaims listed activities result in advantageous developments and improvements of in the independent ones claims specified characteristics. Suitable for connecting the linear actuators to the rotary drive Especially a ratchet lever with a free end or one Ratchet lever with two opposite Lever arms or a movable power transmission means, such as a Toothed or V-belt with two ends.

has the connecting means two opposite Ends on can advantageously be a pneumatic linear actuator at each end be attached, with the other end of the actuator to a rigid Reference point is attached. When the actuator is pressurized, it exerts pressure in each case a tensile force on the connecting means, whereby the rotary drive is set in rotation. Here are the two Linaraktuatoren be arranged in a space-saving manner approximately parallel.

has the connecting means only one end, for example, a single-ended Ratchet lever, can two or more linear actuators opposite one another at this end to be ordered. The one linear actuator is relaxed, while the other is contracting. In this embodiment, the linear actuators can be practically direct be integrated in a manual ratchet mechanism.

Instead of two oppositely acting pneumatic linear actuators one of the two can also be replaced by a spring element, that the default of the connecting element against the length contraction of a linear actuator causes. Such a spring element can easily adapt to the change in length be adapted to the linear actuator and is significantly cheaper in the production as the second linear actuator.

In order to prevent a movement of the rotary drive when a torque acts on the output side (seat part), the ratchet mechanism has a neutral zero point position in which the rotary drive has a self-locking. out Starting from this neutral zero position, the connecting element can be adjusted in two different end positions, whereby in each case a rotation of the rotary drive takes place in one or the other direction.

In an alternative embodiment the ratchet mechanism only interposes a single turning range two end positions, wherein upon actuation of the connecting element in one direction the rotary drive is adjusted in one direction while this one in the opposite direction has a freewheel. The torque transmission direction with the opposite freewheel can be mechanically in the direction changed so that the one turning area for an adjustment of the seat parts is usable in opposite directions.

Especially Cheap it is the torque transmission direction the ratchet mechanism also by means of a pneumatic linear actuator to press, this is optionally supplemented by an elastic return element.

to activity the linear actuators are connected to a control unit, the pressurization of the linear actuators via or regulates several valve units. Are for the seat adjustment larger adjustment paths required, can this by repeated actuation the pneumatic linear actuators can be achieved in succession. It can over the pressure frequency and the length change the linear actuators a quasi-continuous adjustment be set.

there can the linear actuators over Connecting lines directly pressurized by an air pump be, or be supplied by a pressure accumulator, in turn held by a pump at a certain pressure level. To relax the pneumatic linear actuator whose pressure just over a valve to be discharged to the environment.

At the Method for operating two oppositely acting pneumatic Linear actuators is used to adjust the connecting element in the one direction of the first linear actuator pressurized while the second linear actuator is vented simultaneously. This can also be done Linear actuators are used which only when contraction one Apply force to the connecting element. The extension of this The linear actuator is then passed through the contraction of the second linear actuator or a spring element causes the move the connecting element in the opposite direction.

are arranged on a connecting element two linear actuators, the can be operated in alternating cycle, these can be particularly favorable together be controlled by means of a 4-way 3-position valve, wherein the frequency of the clock change is specified by the control unit.

alternative can the two linear actuators but also each by means of two independent 3-way 3-position valves, or 3-way 2-position valves to be connected to the pressure supply.

For the operation of the Ratchet mechanism with a neutral zero point position and two others The end positions corresponding to the two directions of rotation are suitable in particular the control of the at least one linear actuator by means of a Pressure relief element. Through this can specify a pressure level be applied to the linear actuator, and the one certain length contraction equivalent. The first difference in length between the partially contracted position of the linear actuator and the completely relaxed position corresponds to your first ratchet area with a first direction of rotation. It is with the relaxation of the Linear actuator transmits torque to the rotary actuator, while this at the subsequent partial contraction has a freewheel.

to activity of the second ratchet area, the linear actuator is subjected to the maximum pressure, that of a maximum length contraction equivalent. When relaxing to the pre-set intermediate pressure in turn works a freewheel so that in this work area the Rotary drive can be operated in the second direction.

By the use of a restoring element counteracting the linear actuator, can be used advantageously a linear actuator, the only at whose contraction generates a tensile force, since the spring element its expansion causes. This allows for the whole seat half of all Including lineactractors save the pneumatic pressure supply.

By the control of the linear actuator by means of a valve unit, which has a pressure-limiting element, can without electronic Pressure control a defined partial contraction of the linear actuator be achieved. It can be a set pressure even at high Pressure frequency can be repeated exactly without the need for a pressure sensor is necessary.

drawings

In The drawings are several embodiments of inventive seat adjustment shown and explained in more detail in the following description. It demonstrate:

1 a schematic view of Sitzverstellfunktionen,

2 a pneumatic linear actuator,

3 a ratchet device according to the invention with two rotational ranges,

4 a ratchet mechanism according to the invention with switchable torque transmission direction,

5a) to 5c) various arrangements according to the invention of the linear actuators on a connecting element,

6a) to 6c) Variations of the arrangements 5a ) to 5c) with return springs,

7 a drive arrangement for an adjustment function according to the invention,

8th an alternative valve arrangement according to the embodiment according to 7 and

9 a further variation of a seat adjustment device according to the invention.

description the embodiments

In 1 is a vehicle seat 11 shown attached to a mounting surface 12 a body 14 is attached. The seat 11 has various seat parts 15 like the headrest 16 , the backrest 17 , the seat 18 or the seat extension 19 on. These seat parts 15 are against each other with the seat adjustment device according to the invention 10 arranged movably to each other. Furthermore, the seat 11 as a whole opposite the mounting surface 12 be adjusted. The adjusting functions according to the invention relate in detail to the headrest longitudinal position 20 , the headrest height 21 , the headrest tilt 22 , the backrest width 23 , the backrest pillow situation 24 , the lumbar support 25 , the backrest tilt 26 , the seat longitudinal position 27 , the seat depth 28 , the seat height 29 , as well as the seat tilt 30 ,

The seat parts 15 or the seat 11 be using pneumatic linear actuators 32 pretended to be in 2 are shown. The linear actuator 32 has a flexible hose 34 on, at both ends of the end pieces 36 are arranged. A tail 36 forms a connection 38 for pneumatic supply lines 40 , Becomes the linear actuator 32 over the connection 38 with a pressure 42 pressurized, the hose pulls 34 together, what with an extension of its diameter 44 connected is. As a medium for the generation of pressure 42 For example, air is used by means of a pump 50 is compressed. In relaxed state, the linear actuator points 32 a maximum length 46 on, which when pressurized by a change in length 48 along an axial direction 47 is reduced. The change in length 48 may vary depending on the material used of the flexible hose 34 up to 25 percent of the maximum length 46 be. Is this connector 38 on a seat part 15 firmly fixes, practices the opposite tail 36 a tensile force 58 on an associated connecting element 52 on. The second, the connection 38 opposite tail 36 is as a pressure-tight fastener 39 formed, for example, with the connecting means 52 a rotary drive 54 connected as he is in 3 is shown.

3 shows a rotary drive 54 that with a ratchet mechanism 56 is connected and for example between mutually movably arranged seat parts 15 is arranged. The ratchet mechanism 56 here has a neutral rest position 60 on, in which the two seat parts 15 are firmly locked against each other. The connecting element 52 is here as a ratchet lever 64 with a free end 65 formed according to the embodiment in 5a) with pneumatic linear actuators 32 connected is. Will be the connecting element 52 in a first end position 61 moves, while a torque via an output element 55 of the rotary drive 54 - or a force on a subsequent adjustment kinematics - on a seat part 15 transfer. According to the ratchet principle, the ratchet mechanism 56 in the recovery of the connecting element 52 from the first end position 61 in the resting position 60 a freewheel on, so that when resetting the ratchet lever 64 no torque is transmitted. This process can be carried out by means of the at least one linear actuator 32 be repeated as often as necessary, until the seat part 15 has reached the desired position. Should the seat part 15 are reset in the opposite direction, the connecting element 52 from the neutral resting position 60 in the second end position 62 emotional. This is a torque for the rotary drive 54 transferred in the opposite direction, wherein in the provision of the second end position 62 in the neutral resting position 60 again a freewheel acts. Through the neutral rest position 60 is always guaranteed in such an embodiment that when a torque or a force from the seat parts 15 on the rotary drive 54 a mecha nische self-inhibition of the system is given.

4 shows an alternative embodiment of a ratchet mechanism 56 in which the connecting element 52 only within a single range of rotation 63 between a first and a second end position 61 . 62 can be moved. The rotary drive 54 also has a freewheel device, so that when returning the ratchet lever 64 from the second end position 62 in the first end position 61 no torque is transmitted. Because this device is not a neutral resting position 60 has, the torque transmission direction 66 by means of a switch 68 at the rotary drive 64 be switched. The self-locking of the system takes place here for example via a load torque lock 69 , In the embodiment according to 4 becomes the torque transmission direction 66 also by means of a pneumatic linear actuator 32 switched over the pneumatic supply lines 40 and a valve unit 41 with the pump 50 connected is. The seat adjustment device 10 has a control unit 70 on which the activation of the linear actuators 32 both of the ratchet lever 64 , as well as the switch 68 controls.

In the 5a) to 5c) are various embodiments of a Sitzverstellvorrichtung 10 shown, in each case two pneumatic linear actuators 32 are arranged counteracting each other. In 5a) is the connecting element 52 as in 3 as a ratchet lever 64 with a free end 65 trained, at your the two linear actuators 32 opposite with the fasteners 39 are attached. The pneumatic supply lines 40 that with the connections 38 are connected here are not shown in detail. When activating the linear actuators 32 they exert a traction 58 along the axial direction 47 on the connecting element 52 out. In 5b) is the connecting element 52 as a flexible traction device 72 trained, that about a positive connection 73 or a frictional connection 74 with the rotary drive 54 interacts. The traction device 72 has two free ends 75 . 76 on that with the as fasteners 39 trained tails 36 the linear actuators 32 are connected. The linear actuators 32 are with the other tails 36 that as connections 38 are formed, fixed to a seat part 15 For example, the seat back 17 connected. The rotary drive 54 however, is via the output element 55 with a second seat part 15 For example, the headrest 16 connected. The rotational movement of the rotary drive 54 can be used directly to adjust the headrest inclination 52 be used or via a not-shown gear, such as a spindle gear in a headrest height adjustment 21 be implemented. In 5c) is in place of the traction device 72 a rigid ratchet lever 78 with two radially opposite free ends 75 . 76 according to the ratchet principle with the rotary drive 54 connected. Between the fasteners 39 the linear actuators 32 and the free ends 75 . 76 are flexible coupling elements 79 arranged to the rotational movement of the ratchet lever 78 with the linear movement of the pneumatic linear actuators 32 to pair.

The 6a) to 6c) each show variations of the embodiments according to the 5a) to 5c) , where in each case a linear actuator 32 by an elastic return element 80 is replaced. The reset element 80 on the one hand - like the linear actuator 32 - on a seat part 15 firmly fixed and on the other hand with the connecting element 52 connected. The reset element 80 is for example as a tension spring 81 trained, which is a traction 58 on the fastening element 39 exercises. Becomes the linear actuator 32 vented, causes the tensile force 58 of the spring element 80 a provision of the rotary drive 54 over the freewheel, and possibly an extension of the linear actuator 32 to its maximum length 46 , Both the embodiments according to 5a) to 5c) , as well as the embodiments 6a) to 6c) can each according to your ratchet principle according to 3 with a neutral resting position 60 , or according to your ratchet principle 4 with a single rotation range 63 without self-locking rest position 60 operate.

Based on 7 is a method of operating a seat adjuster 10 according to the embodiment according to 5b) with a ratchet mechanism 56 without neutral resting position 60 ( 4 ). The two connections 38 that sit here on the seat 18 as a seat part 15 are fixed via the pneumatic supply lines 40 with the valve unit 41 connected. The valve unit 41 is hereby a 4-way 3-position valve 82 formed (4/3-valve) on which both linear actuators 32 are connected. In the illustrated valve position 2 the pressure stays 42 in both linear actuators 32 unchanged, so that instantly no adjustment of the seat parts 15 he follows. The valve unit 41 is over an accumulator 84 with the pump 50 connected, being a pump motor 51 - as well as the valve unit 41 - from the control unit 70 is controlled. Receives the control unit 70 an adjustment signal 85 , this switches the valve unit 41 such that one of the linear actuators 32 with the maximum pressure 42 is applied, and the other linear actuator 32 is vented by the compressed air to the environment 45 escapes. Is in 7 for example, the valve 41 moved upwards (valve position 3 ), becomes the upper linear actuator 32 with pressure 42 applied. This pulls this linear actuator 32 about the change in length 48 together, so the traction 58 over the connecting element 52 on the rotary drive 54 acts, with a torque on the output element 55 übertra will be. After the maximum contraction of the upper linear actuator 32 turns on the control unit 70 the valve 41 completely down (valve position 1 ), so now the upper linear actuator 32 is completely vented, and at the same time the lower linear actuator 32 with maximum pressure 42 is charged. This pulls the lower linear actuator 32 about the change in length 48 together, while the upper linear actuator 32 completely relaxed. In this direction of rotation of the rotary drive 54 acts on the ratchet principle of the freewheel, so that in this case no torque on the output element 55 is transmitted. The control unit 70 Now specifies the clock frequency with which the valve positions 1 and 3 be changed, whereby by the duration of the pressurization and the length changes 48 the linear actuators 32 can be influenced. Because the linear actuators 32 each against the environment 45 be vented, the control unit ensures 70 for that over the pump motor 51 always a certain pressure level 42 in accumulator 84 is held. If the adjustment of the seat parts 15 be reversed causes the control unit 70 an actuation of the switch 68 for reversing the torque transmission direction 66 , This happens z. B. by means of another linear actuator 32 according to the embodiment according to 4 ,

8th shows an alternative valve arrangement 41 for the embodiment according to 7 where the 4/3 valve is replaced by two independent 3/3 valves. This can be done via the control unit 70 the two linear actuators 32 be pressurized or vented independently. The coordination and timing of the two independent 3/3-valves 86 takes place exclusively via the control unit 70 , The valve unit 41 is in this variation directly from the pump 50 supplied with compressed air, the control unit 70 regulates the desired print request. In an alternative embodiment, instead of the 3/3 valves 86 also be used 3/2-valves, where an interruption of the compressed air supply (valve position 2 ) for both linear actuators 32 is dispensed simultaneously.

Based on 9 Another method for operating a seat adjuster 10 according to the embodiment according to 6b) and a ratchet mechanism 56 with a neutral resting position 60 according to 3 described. The connecting element 52 is here at its first end 75 only with a pneumatic linear actuator 32 and at the other free end 76 with a return spring 80 connected. Because the rotary drive 54 in the neutral resting position 60 is inhibited, becomes the linear actuator 32 for the two torque transmission directions 66 operated in different pressure ranges, resulting in a different change in length 48 of the linear actuator 32 follows. Thus the neutral resting position 60 must be complied with, a certain length of the linear actuator 32 For example, the maximum length will be set 46 by half the maximum length change 48 reduced. At this length is the linear actuator 32 only partially contracted, giving a certain level of pressure 43 corresponds to that with a pressure limiting unit 88 is adjusted with the valve unit 4l is coupled. The connection 38 This is via a 3/3-valve 86 with a pressure supply 84 connected. Parallel to the 3/3-valve 86 is another valve 90 , For example, a 2/2-valve arranged, the vent outlet 91 with the pressure limiting unit 88 connected is. Lies at the control unit 70 no control signal 85 on, both valves are located 86 and 90 in a blocking position (valve position 2 ), in which the applied pressure is maintained. Should a seat part 15 For example, this corresponds to a movement of the connecting element 52 from the neutral position 60 in the first end position 61 , For this purpose, the linear actuator 32 contract, including the 3/3-valve 86 switched down (valve position 1 ) will be to maximum pressure 42 to apply. At the same time, the lower 2/2 valve 90 locked (valve position 2 ), so that in the linear actuator 32 the maximum pressure 42 with a maximum contraction 48 builds. For the freewheel movement from the end position 61 in the neutral rest position 60 must be the linear actuator 32 back to his neutral position 60 expand. This is the valve 86 in the blocking valve position 2 while the 2/2 valve 90 the pressure 42 against the pressure limiting element 88 discharges (valve position 1 ), resulting in the linear actuator 32 the pressure level 43 the pressure limiting element 88 established. This process can be used to lift the seat part 15 be repeated as often as you like.

Should the seat part 15 however, be adjusted in the opposite direction, for example be lowered - must be the connecting element 52 from the neutral resting position 60 in the second end position 62 to be moved, including the linear actuator 32 must expand to the maximum. To do this, vent the valve 86 the linear actuator 32 (Valve position 3 ) against the environment 45 , This relaxation of the linear actuator 32 is through the reset element 80 supported. For the freewheel movement from the end position 62 to the neutral resting position 60 must be the linear actuator 32 partially contract again. For this the valve remains 90 in the pressure limiting position (valve position 1 ), and the valve 86 is a defined time on valve position 1 switched, so here the maximum pressure 42 is applied. This builds up in the linear actuator 32 a pressure on the pressure level 43 the pressure limiting unit 88 corresponds, causing the fastener 39 with the end 75 of the connecting element 52 in the neutral rest position 60 goes. This cycle can also be repeated until the seat part 15 according to the request command 85 is lowered. In this embodiment with the traction means 72 as a connecting element 52 can from the pneumatic linear actuator 32 only tensile forces 58 on the rotary drive 54 be transmitted. Therefore, a linear actuator can also be used 32 be used, for example, only generates an adjusting force during its contraction, and its expansion by the corresponding return spring 80 , or via a second linear actuator 32 according to 7 is produced.

It should be noted that, with regard to the exemplary embodiments shown in the figures and in the description, a variety of possible combinations of the individual features and method steps are possible with one another. For example, the specific arrangement and design of the seat parts 15 to each other, the rotary drive 54 and the connecting elements 52 , as well as the arrangement of the linear actuators 32 and the elastic return elements 80 be varied. Likewise, the ratchet mechanism 56 with regard to its neutral zero position 60 and the direction of rotation of the freewheel - or its reversal - modified. The seat adjustment device according to the invention is particularly suitable for the modification of a manual ratchet mechanism 56 with a blocking neutral rest position and the optional use of elastic return elements 80 , The pneumatic adjusting device can also be combined very favorably with a pneumatic massage or driving dynamics system.

Claims (16)

Seat adjustment device ( 10 ) - in particular for motor vehicle seats - with two relative to each other and / or to a mounting surface ( 12 . 14 ) movably arranged seat parts ( 15 . 16 . 17 . 18 . 19 ) via at least one ratchet mechanism ( 56 ), wherein the ratchet mechanism ( 56 ) a double-acting rotary drive ( 54 ), characterized in that the rotary drive ( 54 ) by means of a connecting element ( 52 . 64 . 72 . 78 ) with at least one pneumatic linear actuator ( 52 ), which upon application of pressure ( 42 . 43 ) axially contracted and thereby the rotary drive ( 54 ) is set in rotation. Seat adjustment device ( 10 ) according to claim 1, characterized in that the connecting element ( 52 ) as a single-end ratchet lever ( 64 ), or as a two-end ratchet lever ( 78 ) or as traction means ( 72 ) - such as a toothed belt ( 72 ) or a chain ( 72 ) - is trained. Seat adjustment device ( 10 ) according to one of claims 1 or 2, characterized in that the connecting element ( 52 ) opposite ends ( 75 . 76 ), at each of which at least one pneumatic linear actuator ( 32 ), wherein a plurality of pneumatic linear actuators ( 32 ) preferably in the axial direction ( 47 ) are arranged approximately parallel. Seat adjustment device ( 10 ) according to one of the preceding claims, characterized in that at a single end ( 65 ) of the connecting element ( 52 ) at least two pneumatic linear actuators ( 32 ), wherein the two linear actuators ( 32 ) counteract each other with their longitudinal contraction. Seat adjustment device ( 10 ) according to one of the preceding claims, characterized in that on the connecting element ( 52 ) - especially at one end ( 65 . 75 . 76 ) thereof - an elastic return element ( 80 ), which is the longitudinal contraction of the at least one pneumatic linear actuator ( 32 ) counteracts. Seat adjustment device ( 10 ) according to one of the preceding claims, characterized in that the ratchet mechanism ( 56 ) a neutral rest position ( 60 ), in which the movement of the seat parts ( 15 ) and two end positions ( 61 . 62 ) for the two directions of rotation ( 66 ), wherein in particular the rotary drive ( 54 ) only then according to the respective direction of rotation ( 66 ) rotates when the connecting element ( 52 ) from the rest position ( 60 ) is moved away, while during a movement of the connecting element ( 52 ) to the rest position ( 60 ), the rotary drive ( 54 ) does not turn. Seat adjustment device ( 10 ) according to one of the preceding claims, characterized in that the ratchet mechanism ( 56 ) only one rotation range ( 63 ) having a freewheel device whose torque transmission direction ( 66 ) by means of a switch ( 68 ) is switchable. Seat adjustment device ( 10 ) according to one of the preceding claims, characterized in that the torque transmission direction ( 66 ) of the ratchet mechanism ( 56 ) by means of at least one pneumatic linear actuator ( 32 ) and / or the elastic return element ( 80 ) is switchable. Seat adjustment device ( 10 ) according to one of the preceding claims, characterized in that the at least one pneumatic linear actuator ( 32 ) via a valve arrangement ( 41 . 82 . 86 . 90 ) with a pressure supply ( 84 . 50 ) and an electronic control unit ( 70 ) is connected to the at least one pneumatic linear actuator ( 32 ) with a predetermined frequency alternately with a pressure ( 42 . 43 ) and at closing again to vent. Seat adjustment device ( 10 ) according to one of the preceding claims, characterized in that the pressure supply ( 84 . 50 ) a pump motor ( 51 ) and / or an accumulator ( 80 ), which via one or more valve units ( 41 . 82 . 86 . 90 ) with the at least one pneumatic linear actuator ( 32 ) are connected. Method for operating a seat adjustment device ( 10 ) - in particular according to one of the preceding claims - with two relative to each other and / or to a mounting surface ( 12 . 14 ) movably arranged seat parts ( 15 . 16 . 17 . 18 . 19 ) with at least one ratchet mechanism ( 56 ), wherein the ratchet mechanism ( 56 ) a double-acting rotary drive ( 54 ), and the rotary drive ( 54 ) by means of a connecting element ( 52 . 65 . 72 . 78 ) with at least two opposing pneumatic linear actuators ( 32 ) are actively connected, whereby these are controlled such that the first pneumatic linear actuator ( 32 ) upon application of pressure ( 42 . 43 axially retracts, while the second pneumatic linear actuator ( 32 ) expands during its venting. Method according to claim 11, characterized in that two pneumatic linear actuators ( 32 ) together by means of a 4-way 3-position valve unit ( 41 . 82 ). Method according to claim 11 , characterized in that the individual pneumatic linear actuators ( 32 ) each by means of an independent 3-way 3-position valve unit ( 41 . 86 ) or a 3-way 2-position valve unit ( 41 ). Method for operating a seat adjustment device ( 10 ) - in particular according to one of the preceding claims - with two relative to each other and / or to a mounting surface ( 12 . 14 ) movably arranged seat parts ( 15 . 16 . 17 . 18 . 19 ), which by means of at least one, a rotary drive ( 54 ) having ratchet mechanism ( 56 ), wherein the ratchet mechanism ( 56 ) a neutral rest position ( 60 ), in which the movement of the seat parts ( 15 . 16 . 17 . 18 . 19 ) and two end positions ( 61 . 62 ) for the two directions of rotation ( 66 ), and the rotary drive ( 54 ) with at least one pneumatic linear actuator ( 32 ) is actively connected, wherein this is controlled such that the pneumatic linear actuator ( 32 ) for the one direction of rotation ( 66 ) between its minimum length and a fraction, in particular half - its maximum length ( 46 ) and contracts while the pneumatic linear actuator ( 32 ) for the opposite direction of rotation ( 66 ) between the fraction - in particular half - of its maximum length ( 46 ) and its maximum length ( 46 ) stretches and contracts. Method for operating a seat adjustment device ( 10 ) - in particular according to one of the preceding claims - with two relative to each other and / or to a mounting surface ( 12 . 14 ) movably arranged seat parts ( 15 . 16 . 17 . 18 . 19 ) with at least one ratchet mechanism ( 56 ), wherein the ratchet mechanism ( 56 ) a double-acting rotary drive ( 54 ), and the rotary drive ( 54 ) by means of a connecting element ( 52 . 65 . 72 . 78 ) with at least one pneumatic linear actuator ( 32 ) and a counteracting, elastic return element ( 80 ), wherein the elastic return element ( 80 ) absorbs potential energy during the pneumatic linear actuator ( 32 ) with a pressure ( 42 . 43 ) and gives off potential energy to the pneumatic linear actuator ( 32 ) during its venting in the axial direction ( 47 ) to stretch. Method according to one of claims 11 to 14, characterized in that the at least one pneumatic linear actuator ( 32 ) for setting a predefinable longitudinal extent ( 48 ) with a pressure limiting element ( 88 ) is operated.